Drip resistant dispensing nozzle

ABSTRACT

A dispensing nozzle method and apparatus is provided that may help in reducing the number of defects in integrated circuits during the manufacturing process. In one embodiment, the nozzle is configured such that at least a portion of the end of the nozzle that dispenses fluid can increase and decrease with a change in pressure, which may help to control fluid drips when the nozzle is not dispensing.

RELATED APPLICATION

The present application is a divisional of U.S. patent application Ser.No. 10/666,992, filed Sep. 19, 2003 now U.S. Pat. No. 7,114,641, andentitled “DRIP RESISTANT DISPENSING NOZZLE,” which is herebyincorporated by reference in its entirety.

FIELD OF THE INVENTION

Disclosed embodiments of the invention relate to the fields ofsubstrates and integrated circuit manufacturing. More specifically,disclosed embodiments of the invention relate to dispensing nozzles thatreduce the tendency of the nozzle to drip fluid when not dispensing.

BACKGROUND

In integrated circuit (such as microprocessor) fabrication process, asubstrate, typically a silicon based wafer, goes through a number ofprocessing steps in order to manufacture completed integrated circuits.Some of these steps include, but are not limited to, oxidation, circuitpatterning, chemical etching, and metal deposition. One process,photolithography, is often used to transfer the pattern representing thecircuit components onto the surface of the substrate.

In the photolithography process, a photo resist material is oftendeposited on the surface of the substrate. A mask is then placed overthe substrate, often in the form of a patterned reticule or otherpattern medium. An exposing source, such as light, passes through thepattern mask and exposes certain portions of the photo resist to createa particular desired circuit pattern. The exposed portion is thenremoved from the substrate using a developer solution.

The developer solution is typically dispensed across the surface of thesubstrate and allowed to briefly stand on the substrate in order toremove the exposed photo resist. The developer solution and the exposedphoto resist are then removed from the substrate with a rinse solution,such as de-ionized water. Once completed, the substrate is ready for thenext step in the process, which may be, for example, the etchingprocess.

One technique often used to dispense and remove developer and the rinsesolution is to slowly rotate the substrate and dispense, via a nozzle,the developer solution on the center of the substrate. The fluid maythen radially distributes across the surface of the substrate. Once thedeveloper has completed its reaction time with the exposed photo resist,the substrate is spun at a much higher revolutions per minute RPM suchthat the developer and exposed photo resist are spun off the substrate.The de-ionized water solution is then similarly dispensed and spun offto insure the exposed photo resist and developer are removed from thesurface of the substrate.

A significant problem exists with dispensing the developer and rinsesolution onto the substrate using the current dispensing nozzles. Due tothe relatively low viscosity and low surface tension of the developerand even lower viscosity and surface tension of the rinse solution, adrip from the nozzle will often occur after the developer or the rinsesolution has been stopped and before an arm carrying the nozzle is ableto move the nozzle away from the substrate. Because of the delicate andunprotected state of the integrated circuits, drips on the substrate arevery undesirable. Drips may cause fatal defects in the patterning of theintegrated circuit directly hit by the drip as well as those in closeproximity.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is illustrated by way of example and not by way oflimitation in the figures of the accompanying drawings, in which thelike references indicate similar elements and in which:

FIG. 1A illustrates a top cross-sectional view of a dispensing nozzle inaccordance with an embodiment of the present invention, where the nozzleis in a dispensing configuration;

FIG. 1B illustrates an end cross-sectional view of the dispensing nozzleof FIG. 1A in accordance with an embodiment of the present invention;

FIG. 2A illustrates a top cross-sectional view of a dispensing nozzle inaccordance with an embodiment of the present invention, where the nozzleis in a non-dispensing configuration;

FIG. 2B illustrates an end cross-sectional view of the dispensing nozzleof FIG. 2A in accordance with an embodiment of the present invention;

FIG. 3A illustrates a top cross-sectional view of a dispensing nozzle inaccordance with an embodiment of the present invention, where the nozzleis in a dispensing configuration;

FIG. 3B illustrates an end cross-sectional view of the dispensing nozzleof FIG. 3A in accordance with an embodiment of the present invention;

FIG. 4A illustrates a top cross-sectional view of a dispensing nozzle inaccordance with an embodiment of the present invention, where the nozzleis in a non-dispensing configuration;

FIG. 4B illustrates an end cross-sectional view of the dispensing nozzleof FIG. 4A in accordance with an embodiment of the present invention;

FIG. 5A illustrates a top cross-sectional view of a dispensing nozzle inaccordance with an embodiment of the present invention, where the nozzleis in a dispensing configuration;

FIG. 5B illustrates a top cross-sectional view of a dispensing nozzle inaccordance with an embodiment of the present invention, where the nozzleis in a non-dispensing configuration;

FIG. 6 illustrates a side view of a rinse process in accordance with anembodiment of the present invention;

FIG. 7 illustrates a side view of a developer solution applicationprocess in accordance with an embodiment of the present invention.

FIG. 8 illustrates a photolithography system in accordance with anembodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof wherein like numeralsdesignate like parts throughout, and in which is shown by way ofillustration specific embodiments in which the invention may bepracticed. It is to be understood that other embodiments may be utilizedand structural or logical changes may be made without departing from thescope of the present invention. Therefore, the following detaileddescription is not to be taken in a limiting sense, and the scope of thepresent invention is defined by the appended claims and theirequivalents.

FIGS. 1A-1B illustrate a top and an end cross-sectional view of adispensing nozzle in accordance with an embodiment of the presentinvention, respectively. Dispensing nozzle 100 is configured to dispensefluid from a fluid source in a controlled fashion. Fluid flows from afirst end 112, which may be sometimes referred to as the intake end,through cavity 113 and out a second end 110, also referred to as thedispensing end. Cavity 113 may be defined by the inner wall portion 115of the nozzle body 114. Nozzle body 114 may be at least partiallyconstructed of a substantially flexible material to allow the nozzlediameter to increase and decrease. Suitable substantially flexiblematerials include, but are not limited polyethylene, polypropylene,latex based materials and the like.

Flow directional arrow 124 indicates this movement of fluid from thefirst end 112 through cavity 113 to the second end 110. As shown, secondend 110 is in the dispensing configuration and has a dispensing or firstdiameter 122, that allows fluid, such as a developer solution orde-ionized water, to be dispensed onto a substrate being processed. Whenthe fluid source is activated (e.g. turned on or a valve (not shown) isactuated) fluid is dispensed through second end 110. When the source isdeactivated, nozzle 100 stops dispensing, but leaves a certain amount offluid, sometimes referred to as standing fluid, in cavity 113. It isduring the time between when the nozzle stops dispensing and the timethe nozzle is moved away from the substrate (or a new substrate ispositioned) that a drip is likely to fall on the treated substrate. Thestanding fluid has a tendency to drip in part because the gravity actingon the standing fluid overcomes the lower surface tension of the fluid,forcing it to drip from second end 110.

To resist this tendency to drip, capillaries 116 may be partially orcompletely disposed within the nozzle body 114. Capillaries 116 mayextend along a portion of the nozzle body to a designated point at ornear second end 110. Capillaries 116 are configured to couple to apressure control source upstream from capillary inlet 118. The pressurecontrol source may be a pump, for example, capable of creating apositive or negative pressure (i.e. a vacuum). By creating a vacuum, forexample, the capillaries may constrict, which may cause thesubstantially flexible nozzle to also constrict.

FIGS. 2A-2B illustrate a top and a side cross sectional view of adispensing nozzle in accordance with embodiment of the presentinvention, respectively, where the nozzle is in the non-dispensingconfiguration. When the fluid source is deactivated or cut off, thepressure control source may create a vacuum, which may cause capillaries216 to constrict or shrink in diameter. Constriction of capillaries 216in turn may cause the inner diameter 226 of second end 210 to decreaseinto a nondispensing configuration (as compared to dispensing diameter122 in FIG. 1A). This decrease in diameter 226 may help resist thetendency of the fluid to drip once the fluid source is cut off, and isparticularly useful for fluids having a lower surface tension.

Reducing diameter 226 decreases the area of the first end 210 that thestanding fluid in nozzle cavity 213 must pass through to drip. Thiseffectively decreases the area of the potential drip and results in ahigher surface tension per opening area. Thus even a slight decrease indiameter 226 results in a greater resistance of the standing fluid todrip once the fluid source is deactivated. This resistance to drippagemay allow time for the nozzle to be moved from a position above thesubstrate, or may allow time for a new substrate to be positioned forprocessing without dripping.

A comparison of FIG. 1B with FIG. 2B illustrates the reduction in thediameter 122 of dispensing end 110 in the dispensing configuration tothe non-dispensing configuration, where capillaries 216 have constrictedand second end 210 has decreased to diameter 226. The slight reductionin diameter from 122 to 226 will likely allow the nozzle, once the fluidsource is cut off, to resist the tendency to drip standing fluid for alonger period of time.

FIG. 3A illustrates a cross sectional view of a dispensing nozzle inaccordance with an embodiment of the present invention. Nozzle 300 is ina dispensing configuration, having an intake first end 312 configured tocouple to a fluid source and a dispensing second end 310 for dispensingfluid as shown by directional arrow 324. Nozzle body 314 has an innerportion 315 that defines cavity 313 and outer portion 317. Capillaries316 are disposed within body 314 in an annular fashion. Capillaries 316are configured to couple to a pressure control source (not shown)through passage 318 disposed within the nozzle body 314. The individualannular capillaries 316 may also be configured to independently coupleto the pressure control source without using passage 318.

FIG. 4A illustrates a top cross sectional view of a dispensing nozzle inaccordance with an embodiment of the present invention in anondispensing configuration. Capillaries 416 are annularly disposed innozzle body 414 toward the second end 410. When the fluid source hasbeen cut off from first end 412 such that no fluid is flowing throughnozzle cavity 413, a pressure control source (not shown) may create avacuum in capillaries 416, which are coupled to the pressure controlsource through passage 418. The negative pressure causes the capillaries416 to constrict, which in turn causes second end 410 to decrease indiameter 426. This decrease in diameter may help nozzle 400 to resistthe tendency to drip fluid for a longer period when the control sourceis cut off from the nozzle.

FIGS. 3B and 4B together illustrate the decrease in diameter 322 to 426when the pressure control source creates a vacuum, thereby constrictingcapillaries 316 down to those capillaries 416.

Though the capillaries described in the embodiments discussed above runin either the longitudinal direction (FIGS. 1-2) or an annular fashion(FIGS. 3-4), it can be appreciated that other configurations arepossible to reduce the nozzle diameter, including, but not limited tocapillaries positioned in a helical fashion. Further, the entire nozzlebody needs not be made of such flexible or pliable material. Forexample, the interior wall portion may be pliable such that the innerdiameter may decrease without the overall diameter of the nozzledecreasing. Or, the lower portion of the nozzle body near the dispensingend may be more pliable such that it reduces in diameter where the upperportion does not.

It can also be appreciated by one of skill in the art that the pressurecontrol source may also increase the pressure thereby expanding thecapillaries of the above described embodiments to decrease the innerdiameter of the nozzle. FIGS. 5 and 5A also illustrate cross sectionalviews of a nozzle in accordance with an embodiment of the presentinvention, where a positive pressure is applied to reduce the nozzlediameter.

FIG. 5A shows a dispensing nozzle 500 in a dispensing configuration inaccordance with an embodiment of the present invention. First end 112 ofnozzle 500 is coupled to a fluid infeed line 530, which is coupled to afluid source (not shown). An inflatable bladder 516 surrounds the cavity513 portion of the nozzle 500. Bladder 516 is coupled to a pressurecontrol source via line 518. Second end 510 is in the dispensingconfiguration having diameter 522. Bladder 516 is in a substantiallynoninflated state, thereby allowing the nozzle to be in a dispensingconfiguration.

FIG. 5B illustrates nozzle 500 in the nondispensing configuration inaccordance with an embodiment of the present invention. When the fluidsource is cut off, the pressure control source inflates bladder 516′.Semi-rigid sleeve 519 surrounds the outer portion of bladder 516′ toprevent the bladder from expanding radially outward when inflated. Byexpanding inward, bladder 516′ causes the nozzle cavity 513 to decreasein diameter at the second end 510. As discussed above, the decrease indiameter shown by 522′, may help prevent any of the standing fluid incavity 513 to resist dripping for a longer period of time. Semi-rigidsleeve 519 is not necessary, as the bladder may be designed to resistoutward expansion, or the outward expansion may be acceptable if thereis also inward expansion.

It can be appreciated that the bladder need not extend longitudinallythe length of the nozzle, but may simply be a short portion locatedtoward the second end to accomplish the same result. Further, though theexample embodiments described herein require the pressure control sourceto either increase or decrease pressure to decrease the diameter of thedispensing end, it can be appreciated that the nozzle may be configuredto be in the non-dispensing configuration in its neutral state. Wherethis is the case, the pressure control source may constrict thecapillaries, for example, in order to enlarge the diameter of thedispensing end.

FIGS. 6 and 7 illustrate cross sectional views of dispensing nozzles inaccordance with embodiments of the present invention. FIG. 6 illustratesthe de-ionized rinse process, where the developer solution is washed offa substrate. Rotatable arm 654 carries nozzle 600 through support 660and linkage 650. Nozzle 600 is coupled to a fluid source of de-ionizedwater (not shown). When dispensing fluid onto substrate 656, nozzle 600may be positioned above the substrate 656 in the dispensingconfiguration.

When the rinse is sufficiently complete, the fluid source is cut off andthe nozzle is placed in the nondispensing configuration by a pressurecontrol source increasing or decreasing the pressure in the capillaries,inflating the bladder, or modify the pressure of another controlmechanism to cause the dispensing end of the nozzle to decrease indiameter. This in turn may help the de-ionized water standing in thenozzle 600 to resist dripping as the rotatable arm moves the nozzle awayfrom a position above the substrate 656.

FIG. 7 illustrates the developer solution dispensing process. Rotatablearm 754 is coupled to nozzle carrier 750, which in turn have multiplenozzles 700 coupled thereto. Conduit 752 is coupled to a fluid source ofdeveloper solution (not shown) through line 758. When dispensing fluidonto substrate 756, nozzles 700 may be positioned above the substrate756 in the dispensing configuration.

When the appropriate amount of developer solution is dispersed onsubstrate 756, the fluid source is cut off and the nozzles 700 may beplaced in the nondispensing configuration. This is accomplished by apressure control source 762 increasing or decreasing the pressure in thecapillaries, inflating the bladder, or modifying the pressure in othercontrol mechanisms to cause the second end to decrease in diameter. Thisin turn may help the developer solution remaining in nozzles 700 toresist dripping as the rotatable arm 754 moves the nozzle carriers 750away from a position above the substrate 656.

FIG. 8 illustrates a photolithography system in accordance with anembodiment of the present invention. Photolithography system 800includes a photo resist applicator 810 for applying photo resistmaterial to a substrate 818. An exposure source 812 may be used forexposing the photo resist through a patterned mask. A nozzle carrier 814carries at least one nozzle 816, which is a drip resistant nozzle of thepresent invention. The nozzle 816 may dispense fluid such as developersolution and/or de-ionized water rinse on the substrate 818 to removeany exposed photo resist.

Though the nozzles described with respect to the various embodiments ofthe present invention have been presented as being useful in thephotolithography process, it is contemplated that the nozzles may beused for any fluid and in any situation where resistance to drippage isneeded, especially when using low viscosity fluids having low surfacetension.

Although specific embodiments have been illustrated and described hereinfor purposes of description of the preferred embodiment, it will beappreciated by those of ordinary skill in the art that a wide variety ofalternate and/or equivalent implementations calculated to achieve thesame purposes may be substituted for the specific embodiment shown anddescribed without departing from the scope of the present invention.Those with skill in the art will readily appreciate that the presentinvention may be implemented in a very wide variety of embodiments. Thisapplication is intended to cover any adaptations or variations of theembodiments discussed herein. Therefore, it is manifestly intended thatthis invention be limited only by the claims and the equivalentsthereof.

1. A method for dispensing fluid in a photolithography process,comprising: providing a dispensing apparatus including: a fluid conduitincluding a first end and a second end, the first end configured tocouple to a fluid source; a nozzle body including an intake end coupledto the second end of the fluid conduit to recieve fluid from the fluidconduit, a tip end configured to receive fluid from the intake end anddispense fluid away from the fluid conduit and the nozzle body, and aninterior cavity configured to allow at least a portion of the interiorcavity to decrease in diameter in response to a pressure change; and aninflatable bladder disposed about a portion of the nozzle body, thebladder configured to couple to a pressure control source to selectivelyeffect the pressure change; coupling the fluid conduit to the fluidsource selected from a group consisting of a photoresist, a developersolution, a rinse solution, and water; dispensing the selected fluidfrom the tip end onto a substrate; and decreasing a diameter of the tipend by changing the pressure.
 2. The method of claim 1, whereindecreasing the tip end includes inflating the bladder.
 3. The method ofclaim 1, wherein the decreasing the tip end comprises decreasing thediameter of the tip end to a greater extent than the intake end of theinterior cavity.
 4. The method of claim 1, wherein the decreasing thetip end comprises decreasing the diameter of the tip end comprisesdecreasing the diameter of the tip end in response to a deactivation ofthe fluid source.
 5. The method of claim 1, further comprisingincreasing the diameter of the tip end by changing the pressure.
 6. Themethod of claim 5, wherein increasing the tip end includes deflating thebladder.